1. Field
The present invention relates generally to navigation systems and, more particularly, to wireless navigation information systems.
2. Description of the Related Art
With the introduction of greater geographic coverage and higher bandwidth wireless connections, wireless carriers and telematics service providers are expected to provide greater functionality and utility in their services. Telematics offers location-based voice and data communication tools to mobile users, and provides “smart” information tailored to user location and purpose of the task. The wireless carriers and telematics service providers focus primarily on navigation devices and systems that provide services and functionality based on a knowledge of the current and/or expected geographic location of the mobile device or user.
The navigation systems generally operate within a navigation area and rely on an ability to find and use locations and connectivity within a map database of the navigation area. Most of the navigation map databases include at least geographic information for major road networks, and will often include additional route information relating to minor roads, road connectivity and accessibility (e.g., one-way streets, turn restrictions at junctions, and other related parameters), road shape information, a database of road names, building number ranges, and points of interest, such as restaurants and shopping malls. Navigation systems can be categorized into either standalone devices, which may optionally have some network connectivity, or server-based systems providing services to low capability devices or thin-client devices such as cell phones.
Recently, some of the most popular of the location-aware standalone devices have been navigation systems installed in vehicles, either by the vehicle manufacturer, or by a dealer as an after-market product. These are typically closed, proprietary systems that include a navigation computer, a display, a means for user input, and some form of bulk data storage device, such as a CD or DVD containing a map database. Commercial navigation map databases are generally proprietary both in terms of the actual physical storage format as well as the access mechanism (e.g., an Application Programming Interface (API) specification) that allows a navigation application of the navigation computer to read and process the data.
The user can enter or select an address of interest and can use the map database to convert the addresses into geographic map positions. These may then be used to generate routing information from an initial geographic location to the map position of interest. In combination with information from various vehicle sensors, for example Global Positioning System (GPS) receivers, gyroscopes, and speed pulse generators, the routing information can then be used to guide the user along the route, giving suitable visible and audible instructions for maneuvering. The map database may also be used to render a map display to the user on a suitable display device.
Such standalone systems, however, are constrained by the content and volume of the map database that, due to space limitations, might not include dynamic characteristics of the road network such as the effect of traffic, weather, or other road conditions. Navigation quality is also limited by the relatively static nature of the database. Due to the logistics involved in creating and distributing CD's and DVD's, standalone systems might only be updated a few times per year with data that could already be several months old when the distribution media is created. Furthermore, because of the generally proprietary nature of the map data, the end user usually only has a single source for the map data, and is therefore also subject to the limitations of the supplier's ability to generate navigation quality data.
Server-based systems have been providing navigation-style services to end users. These services can range from Internet-based systems such as the “MapQuest”™ mapping service accessible through web browsers, to services provided via an operator at a telephone call center, such as those provided by the “OnStar”™ vehicle navigation service. While these services maintain the benefit of having a central map database, which can be kept up-to-date much more readily than standalone systems, the lack of direct local access to this central map database from the client device reduces the overall system functionality. Typically, these services perform most of the data access and information processing, such as route calculation, on the server and then provide the results, in some simple form, to the client device.
For map display, a simple image is typically provided in either raster or vector form to a display device. While a simple image is generally sufficient for rendering the image to a display device, it usually lacks sufficient additional information to enable it to be used for navigation purposes and connectivity information. In the case of the “OnStar”™ service, for example, routes are provided to the client as simple sets of text instructions that are read to the user over a cellular voice call, while map displays are typically provided by sending raster images, or simple vector images. However, neither text instructions nor raster images can provide attribute or connectivity information for the road network.
It should be apparent from the discussion above that current navigation systems employing telematics services could benefit from greater capability and flexibility. Thus, there is a need for an improved navigation system. The present invention satisfies this need.